ZR1 History and Overview

Corvette ZR1 History and Overview

The ZR1 (or ZR-1 ? note the dash) is a high-performance edition of
the Chevrolet Corvette. In and out of production from the late 1960s
until the present time, today’s version is known as the C6 ZR1 Corvette
(no dash). The car’s engine, in combination with the vehicle’s
transmission, suspension and other factors, make it one of the most
powerful, and one of the fastest, automobiles on the road today.

Engine and Transmission

Today’s ZR1’s engine is called the LS9. It is a highly modified
version of the LS3 engine and produces a massive 638 horsepower (476 kW)
and 604 ft. lbs. (or 819 N?m) of torque. The engine features a
supercharger (with intercooler), oil injectors (first time ever on a
production Corvette), titanium connecting rods and inlet valve, aluminum
cylinder heads, and the dry-sump oil system. A unique fuel pressure
regulator supplies fuel at two different pressures, according to the
engine’s rpm. The six-speed manual transmission includes a MH3 gear
set, a lighter flywheel (compared to previous versions), and a
twin-plate clutch.

Suspension, Body, and Frame

The ZR1’s suspension is a double wishbone design. The Corvette also
features ?Magnetic Selective Ride Control.? This system adjusts shock
absorber damping every millisecond for better traction and cornering,
while reducing bounce at launch. The chassis of the C6 ZR1 is made of
aluminum, and many of the car’s body panels are constructed of carbon
fiber, including the hood, fenders, rocker extensions, and splitter.

The current ZR1 has a window in the hood made of polycarbonate, which
allows viewing of the engine’s intercooler. The Corvette also features
blue engine covers, brake calipers, and badges; functioning,
engine-cooler air vents on the fenders; and an over-sized rear spoiler.

The C6 ZR1 is hand built at GM’s Bowling Green, Kentucky, U.S.A.
plant; the engines are manufactured at the company’s Performance Build
Center in Wixom, Michigan, U.S.A.

Past ZR-1s

The first high performance Corvette, called the ZR-1 (with dash),
could be had as an optional engine package on the C3 Corvette. Available
from 1970-1972, the package could only be purchased on the small block
LT-1 engine and featured solid lifters, power brakes, a heavy duty
four-speed transmission, updated suspension (special shocks and springs,
brakes, stabilizer bar), and an aluminum radiator. The car was
manufactured with racing in mind so it came without the normal amenities
like a radio, power steering and wheel covers. Fifty-three of these
Corvettes were produced, making the car a much sought-after collector’s
vehicle.

The C4 ZR-1 Corvette began production in 1990. It featured an engine
built by Lotus, which was then a subsidiary of GM. This engine had an
aluminum block, four overhead camshafts, and 32 valves. The motor also
had an air-management system. This allowed a ?part throttle? condition
which provided the option of turning off eight of the 16 intake runners
and fuel injectors. A valet key allowed the driver to switch between
full and normal throttle. Normal throttle produced 200 horsepower; at
full throttle, the engine put out 375 horse power.

At the time, General Motors had nowhere to manufacture the C4 ZR-1
engine, so it was produced by an outside manufacturer, Mercury Marine,
in Stillwater, Oklahoma, U.S.A.

Lotus also helped develop the ZR-1’s suspension system. Known as the
FX3, this ?active suspension system? would soon become the foundation
for all optional Corvette suspension systems.

Other distinguishing features of the C4 ZR-1 are wider rear wheels and a unique rear stop-lamp position.

Production of the C4 ZR-1 concluded in 1995 after 6,939 units were made.